Process for cleaning spinnerets



March 7, 1961 B. J. VAN DONGEREN 2,974,070

PROCESS FOR CLEANING SPINNERETS Filed Jan. 24, 1958 INVENTOR. BERNHARD JOHANN VAN DONGEREN BY M TT NEY PROCESS FOR CLEANING SPINNERETS Bernhard Johann van Dongeren, Arnhem, Netherlands, assignor to American Enira Corporation, Enka, N.C., a corporation of Delaware Filed Jan. 24, 1958, Ser. No. 711,048 Claims priority, application Netherlands Feb. 7, 1957 Claims. (Cl. 134-1) The present invention relates generally to the cleaning of articles provided with minute orifices by the use of moving liquid and in particular to a process employing an ultrasonic vibration principle for cleaning the orifices of spinnerets or spinning plates used in the production of artificial yarn.

Flowing or moving liquids have of course been used for some time for cleaning apertured articles, such as spinnerets, that have become clogged or contaminated through extended use. In one system, for example, the articles are first rinsed or soaked in running water, after which a jet or stream of water under pressure is forced against the article with the effect, presumably, of removing all impurities from within the apertures or orifices. Accordingto another system, the orifices are cleaned by brushing the spinneret or other articles with water or other cleansing agents.

The aforesaid cleaning systems have not proved entirely satisfactor however, especially for the cleansing of spinneret orifices of extremely small diameters. Not only do these systems have little cleaning effect on the minute orifices, but, additionally, it cannot be determined during treatment if all of the orifices are completely free of impurities. Moreover, considerable time is required for effective cleaning if these systems are employed.

An important object of the present invention, therefore, is to provide a cleaning process not having the disadvantages of known cleaning systems.

Another object of this invention is to provide a process for effectively cleansing the apertures of spinnerets or other articles.

Still another object of the present invention is to provide a process for cleansing the minute orifices of spinnerets in a relatively short period of time.

A specific object of this invention is to utilize an ultrasonic vibrating liquid principle for cleaning clogged or contaminated spinneret orifices.

A further object of the present invention is to provide a process involving concentrating the cleaning action of moving liquid in order to increase the effectiveness thereof.

An additional object of this invention is to provide a spinneret cleaning process during the practice of which the extent of orifice clogging may be readily ascertained visually.

Other objects and advantages will become apparent from the following description of a preferred embodiment.

The disadvantages of known cleaning systems, mentioned hereinabove, are obviated in the practice of the present invention by the application of treating liquid under pressure to each of the orifices of the article to be cleaned. Additionally, the operator may observe, during the cleaning operation, when each orifice has been completely cleaned. The time required for a normal cleaning cycle may be reduced substantially because of the jet stream action of liquid on the orifices and the operator can determine by visual inspection the exact moment e- TCC when all of the orifices are cleaned and immediately" thereafter discontinue the operation.

The foregoing objects and advantages may be obtained if, in accordance with the present invention, a bundle of ultrasonic vibrations directed upwardly is generated in a body of cleaning liquid and if the bundle converges with the focal point thereof lying in or near the surface of the liquid. The article to be cleaned should be brought into the bundle with the face containing the orifices extending transversely of the axis of the bundle and into the boundary layer of liquid.

By the use of this cleaning system, it may easily be ascertained when all of the orifices have become completely flushed since small fountains are formed when the cleaning liquid is forced through the orifices. By experimentation and practice, the operator may determine the degree each orifice is cleansed merely from visual inspection of the shape of the respective fountains. v The generation of a converging bundle of ultrasonic vibrations may be accomplished in any known manner. For example, a cylindrical bundle of ultrasonic vibrations generated by a piezoelectric crystal may be converted into a converging bundle by the use of a lens or by reflection on a hollow mirror. Conversely, the piezoelectric crystal itself may be provided with a curved surface. phenomenon, per se, is generally known in the field of ultrasonic engineering and will not be discussed in detail herein. It is also known, generally, that when a bundle of upwardly directed and converging ultrasonic vibrations are generated in a body of liquid, with the focal point of the bundle lying in or near the liquid surface, a column of liquid rising from said surface is produced. This particular phenomenon still occurs if the focal point of the bundle lies a few centimeters below the liquid surface, determined from an undisturbed condition of the latter. As used here, it is intended that the term near include a-distance of a few centimeters downwardly from the liquid surface.

According to this invention, the phenomena discussed above are used to indicate when the orifices are completely cleaned. When this condition is reached, the cleaning may of course be terminated immediately, which promotes a cleaning operation that is more efiicient than has been known heretofore. In this connection, it is pointed out that the article to be cleaned should not be submerged in the liquid to such an extent as'to prevent the formation of fountains as cleaning liquid is forced through the orifices, since these fountains are of fundamental sigh- 'ificance insofar as concerns determination of complete cleansing. With regard to extent of cleaning, the best criterion is obtained if, according to this invention, the article to be cleaned is positioned with the orifice-containing face thereof slightly above the liquid level. This avoids possible deformation of the fountains bythe presence of liquid above the article during cleaning.

In order to prevent spraying of the cleaning liquid as much as possible, it is preferred that the focal 'point of' 1y transversely to the direction of the bundle during clean- 0 ing in order that the orifices located adjacent the periphery of the article also be exposed to treatment.

The above described system is especially suitable for the cleaning of spinnerets after the same have been polished, which usually leaves the orifices filled with the polishing agent.

This

This may be removed satisfactorily with halogenated hydrocarbons, preferably with trichloro ethylene. This cleaning system has a particular advantage, if the last mentioned cleaning liquid is used, in that evaporation or atomization of the liquids, which is generally noxious and harmful to the operator, is reduced to a minimum. As a consequence of this, very little air conditioning is required at the cleaning station.

For a further discussion of this invention, attention is now directed to the drawing, which illustrates, partly in perspective and partly in side elevation, a preferred embodiment of an apparatus for carrying out the cleaning process disclosed herein.

The apparatus for cleaning spinneret orifices by the principle of ultrasonic vibration is indicated generally in the drawing by reference numeral 10. The cleaning apparatus as shown comprises an outer container 11 formed from glass, an inner vessel 12 formed from metal, a beaker 13 and means indicated generally at 14 for generating and focusing a bundle of ultrasonic vibrations. A piezoelectric plate 15 of quartz, of which only the parallel planar surfaces are metallized, is positioned beneath an opening defined by 16 and provided substantially centrally of inner vessel 12. The upper surface of plate 15 is spaced from a bottom plate 17 of inner vessel 12 by a rubber washer 18 wrapped in tin foil which engages the upper surface of plate 15 as well as the lower surface defining opening 16 and seals these members.

A metal contact plate 20 is disposed in alignment with and below the piezoelectric plate 15. This metal plate is separated from the piezoelectric plate by washer 21 and the plates and washer together define an air chamber 22. In order to effect an electrical contact between the lower metallized surface of quartz plate 15 and contact plate 20, a wire packing 23 is positioned within air chamber 22. The packing is of course provided in sufficient quantity to insure contact of both the upper and lower plates.

The assembly described above, including the quartz plate 15, the contact plate 20, washers 18 and 21 and wire packing 23, is urged into the position shown by pressure plate 24, which is attached to the bottom plate 17 of inner vessel 12 by stud bolts 25. The metal contact plate 20 is connected through a metal conductor 26 and connecting screw 27 to one side of a high-frequency generator (not shown). This generator may be of known construction and, therefore, will not be described in detail. It will be evident to those skilled in the art that the other lead of the generator must be grounded.

The connecting screw 27 passes through a suitable aperture provided in the bottom of outer container 11 and therefore is supported by this container. Glass container 11 also supports the inner vessel 12 in the manner shown. For this purpose the upper rim of vessel 12 is flared outwardly, or flanged, as shown at 28 in order to overlie the upper edge of the outer container. A washer 30 seals the space enclosed by the inner vessel and outer container, as shown. The flange 28 is apertured in order to receive a plurality of drawbolts 31, which bolts also pass through flanged plate 32 positioned at the bottom of the container 11. Nuts are provided on the end of the drawbolts in order to urge the vessel and container together.

As shown in the drawing, one of the drawbolts 31 supports an electrical terminal 33, which terminal is secured in position by nut 34. The electrical terminal is grounded in a conventional manner (not shown) and the space between the inner vessel and outer container is substantially filled with transformer oil.

The aforesaid beaker 13 is positioned within the inner vessel 12 in the manner shown. An annular sleeve 35 is secured to the lower end of this beaker and protrudes downwardly into engagement with the bottom plate 17. The diameter of sleeve 35 is slightly greater than the diameter of opening defined by 16 in order that the beaker and sleeve will completely surround this opening. The

bottom 36 of beaker 13 is formed from phenol form aldehyde resin and is provided with a concave portion 37 preferably having a radius of 35 mm. It can be seen by this construction that the bottom 36 may operate as a lens to convert a cylindrical bundle of ultrasonic vibrations generated by the quartz plate 15 into a converging bundle. The focal distance of the lens in this embodiment amounts to 55 mm.

It is to be pointed out that the distance between the upper side of quartz plate 15 and the lower side of the lens-shaped bottom 36 should be adjusted in order to obtain a maximum transmission of vibrations. It has been found that this maximum condition exists if the aforesaid distance is equal to the product of the half wave length of the ultrasonic vibrations in the transfer medium'with which the inner vessel 12 is filled multiplied by a whole number. More will be said about this medium hereinafter.

Ports 38 are provided in the corner of the apparatus between the annular sleeve 35 and the bottom 36 of the beaker. These deaeration ports, which are provided over the periphery of the sleeve, permit the transfer liquid from inner vessel 12 to fill completely the space between the beaker and the quartz plate 15. The vertical cylindrical wall of the beaker is formed from aluminum.

In the event that a clogged spinneret must be cleaned in the apparatus described with a volatile organic solvent, the inner vessel 12 is filled with a transfer liquid such as water and the beaker 13 is filled with the organic cleaning liquid. The quantity of the organic liquid is so selected that the liquid surface in the inoperative position of the apparatus is about 1 cm. above the focal point of the lens 36.

After the vessel and beaker have been filled, the highfrequency generator is put into operation by increasing the voltage thereof gradually. As a result of this manipulation, a liquid column directed upwardly is formed in the center of the liquid surface in the beaker, during which time atomizing occurs. A clogged or otherwise contaminated spinneret 40 now may be placed in the beaker 13 at the apex of the converging liquid column with the oustide of the spinneret facing upwardly. It is preferred that a suitable holder, such as shown at 41, be provided for surrounding and maintaining the spinneret in position during the cleaning operation. By the use of such a holder, the spinneret may be held with the substantially fiat, orifice-containing face thereof transversely of the axis of the bundle of vibrations on a level slightly above the undisturbed liquid surface around that portion of liquid forming the column. Moreover, the spinneret should be repciprocated slowly to and fro during cleaning. Shortly after the spinneret is positioned over the column, there will appear smaller columns, or fountains, one for each of the cleaned or partially cleaned orifices. As mentioned above, with practice, the operator will be able to determine when cleaning is completed merely by inspection of these small fountains. In general, all of the orifices will be completely cleaned in about 15 secends.

The time requiredfor cleaning contaminated spinnerets in the practice of this invention is appreciably less than that required for cleaning with brushes, particularly in the event that spinncrets having a large number of orifices are to be cleaned. A substantial portion of this saving in time results from the fact that the operator may determine immediately when cleaning has been completed. By the use of the present invention, therefore, frequent prolonged cleaning cycles may be avoided. Furthermore, since the total of the bundle of vibrations is concentrated on the article to be cleaned, the loss in treatment liquid due to atomizing is negligible.

It is, of course, possible to modify the above-described apparatus without departing from this invention. The cylindrical beaker wall extending above the lens 36 may be omitted, if desired, in which case only the lens would be provided. In this event, however, it will be necessary to fill the inner vessel 12 with the treating or cleaning liquid. Moreover, the lens 36 may consist of material other than phenol formaldehyde resin such as, for example, polystyrene or polymethacrylate or any other material operating satisfactorily for transmitting ultrasonic vibrations. It is pointed out, however, that this material must resist chemical reaction of the cleaning liquids. It is also possible to form the concave surface in the quartz plate 15, in which event the lens 36 would not be required.

The process described herein may be used for the cleaning of all types of spinnerets, including spinning plates used in melt spinning. Further, it is possible to clean sieve plates or other articles provided with small orifices. These orifices should extend through the plate, of course, in order to form a passageway for the treating liquid.

The present invention is also applicable to the cleaning of articles with liquids other than those described herein. For example, other organic liquids, emulsions or aqueous solutions could be utilized.

Although a specific embodiment has been described hereinabove, it is intended that this embodiment be construed as one illustration only and that the invention be limited only to the extent specified in the appended claims.

What is claimed is:

1. A process for cleaning contaminated articles hawng a substantially fiat face provided with minute orifices in a body of cleaning liquid comprising the steps of directing a bundle of ultrasonic vibrations upwardly toward the completely Y surface of said liquid, converging the bundle of vibrations into a focal point near the surface of said liquid, and

positioning the article to be cleaned above said focal point in the boundary layer of said cleaning liquid with the substantially fiat, orifice-containing face of said articles extending transversely of the axis of said bundle of vibrations, whereby said vibrations will force said cleaning liquid through the orifices in the form of small fountains and the extent of orifice cleaning may be determined visually during the operation.

2. A process as set forth in claim 1 wherein the orificecontaining face of [the article is positioned slightly above the surface of the body of liquid.

3. A process as set forth in claim 1 and further comprising the step of slowly reciprocating the article transversely of the bundle during cleaning.

4. A process as set forth in claim 1 wherein the cleaning liquid consists of a halogenated hydrocarbon.

5. A process as set forth in claim 1 wherein the level of said cleaning liquid, in inoperative condition, is about 1 cm. above the focal point of said bundle of vibrations.

References Cited in the file of this patent UNITED STATES PATENTS 2,388,836 Dunn Nov. 13, 1945 2,634,738 Fuller Apr. 14, 1953 2,814,575 Lange Nov. 26, 1957 2,831,785 Kearney Apr. 22, 1958 2,845,077 Branson July 29, 1958 2,855,526 Jones Oct. 7, 1958 

1. A PROCESS FOR CLEANING CONTAMINATED ARTICLES HAVING A SUBSTANTIALLY FLAT FACE PROVIDED WITH MINUTE ORIFICES IN A BODY OF CLEANING LIQUID COMPRISING THE STEPS OF DIRECTING A BUNDLE OF ULTRASONIC VIBRATIONS UPWARDLY TOWARD THE SURFACE OF SAID LIQUID, CONVERGING THE BUNDLE OF VIBRATION INTO A FOCAL POINT NEAR THE SURFACE OF SAID LIQUID, AND POSITIONING THE ARTICLE TO BE CLEANED ABOVE SAID FOCAL POINT IN THE BOUNDARY LAYER OF SAID CLEANING LIQUID WITH THE SUBSTANTIALLY FLAT, ORIFICE-CONTAINING FACE OF SAID ARTICLES EXTENDING TRANSVERSELY OF THE AXIS OF SAID BUNDLE OF VIBRATIONS, WHEREBY SAID VIBRATIONS WILL FORCE SAID CLEANING LIQUID THROUGH THE ORIFICES IN THE FORM OF SMALL FOUNTAINS AND THE EXTENT OF ORIFICES CLEANING MAY BE DETERMINED VISUALLY DURING THE OPERATION. 